In the last few decades intensive efforts were undertaken to produce alternative environmentally-friendly processes as a result of the environmental problems associated with the well-known viscose process. One of the most interesting things to take shape in the recent past was the possibility to dissolve cellulose in an organic solvent without the formation of a derivative and to extrude moulded bodies from this solution. Fibres spun from solutions of this kind were given the generic name of Lyocell by BISFA (The International Bureau for the Standardization of Man-Made Fibres) whereby a mixture of an organic chemical and water is meant by an organic solvent. Moreover, fibres of this kind are known as "solvent spun fibres".
It has turned out that a mixture of a tertiary amine oxide and water is particularly well suited as the organic solvent for the production of Lyocell fibres respectively other moulded bodies N-methyl-morpholine-N-oxide (NMMO) is thereby principally used as the amine oxide. Other suitable amine oxides are disclosed in EP-A 0 553 070. Processes for the production of cellulosic moulded bodies from a solution of cellulose in a mixture of NMMO and water are for example disclosed in U.S. Patent Ser. No. 4,246,221 or PCT-WO 93/19230. In this respect the cellulose is precipitated from the solution into an aqueous precipitation bath. Fibres manufactured in this way are characterised by a high fibre tenacity in a conditioned and wet state, a high wet modulus and a high loop strength.
One special property of these fibres is the high propensity to fibrillate, particularly when put under strain in a wet state, such as happens for example during the washing process. Whilst this property is perfectly desirable for certain fibre applications and produces interesting effects, the workability for other purposes, such as textiles for example, which should be wash-resistant, is reduced.
Thus, no effort was spared to reduce the fibrillation behaviour with various measures.
Numerous publications deal in particular with the possibility to reduce the tendency to fibrillate of the fibres by treating these with substances which have a cross-linking effect on cellulose.
According to EP-A-0 538 977 the fibres, which can be either freshly spun or already dried, are treated in an alkaline milieu with an aqueous system which contains a chemical reagent with 2 to 6 functional groups which can react with cellulose. In EP-A-0 538 977 derivatives of cyanuric chloride, and substituted dichlortriazines in particular, are named as suitable substances. Moreover, addition products of cyanuric chloride and poly(ethylene glycol) monomethylether are used.
From EP-A-0 616 071 it is known that fibre materials containing cellulose, such as textiles for example, should be treated amongst other things with metallic salts of partial hydrolyzates of cyanuric chloride to give the textiles crease resistant and easy care properties. The use of substances of this kind to treat solvent spun fibres is not, however, mentioned.
In relation to the reduction of the tendency to fibrillate of cellulosic moulded bodies, which are shaped from a solution of cellulose in tertiary amine oxides, no publication exists to date despite numerous efforts in this field which describes the use of multifunctional textile agents the effect of which justifies the, in the main, high price of these substances.